Johannesburg is one of the dangerous place in South Africa, particularly in Benoni. As you walk in the streets, just in case your place/hotel is nearby the shopping malls, you have to be careful as you walk and better yet, have someone to walk with you and avoid being alone in most times.
As you walk especially with valuable items in the streets, a person or group of young men will approach you to give them your phone (in most cases), wallet or any valuable items. They would ask you to give it to them and would not snatch it from you as it will create a scene. If they are kind, they might give you your sim card. However, If you refuse to give it to them, they will show their knives to you as showing that they are willing to attack you if you are not in favour for what handing out what they’re asking.